Protein kinases are enzymes that catalyze the phosphorylation of hydroxyl groups of tyrosine, serine, and threonine residues of proteins. Many aspects of cell life (for example, cell growth, differentiation, proliferation, cell cycle and survival) depend on protein kinase activities. Furthermore, abnormal protein kinase activity has been related to a host of disorders such as cancer and inflammation. Therefore, considerable effort has been directed to identifying ways to modulate protein kinase activities. In particular, many attempts have been made to identify small molecules that act as protein kinase inhibitors.
The c-Met proto-oncogene encodes the Met receptor tyrosine kinase. The Met receptor is a 190 kDa glycosylated dimeric complex composed of a 50 kDa alpha chain disulfide-linked to a 145 kDa beta chain. The alpha chain is found extracellularly while the beta chain contains transmembrane and cytosolic domains. Met is synthesized as a precursor and is proteolytically cleaved to yield mature alpha and beta subunits. It displays structural similarities to semaphorins and plexins, a ligand-receptor family that is involved in cell-cell interaction. The ligand for Met is hepatocyte growth factor (HGF), a member of the scatter factor family and has some homology to plasminogen (Longati, P. et al., Curr. Drug Targets 2001, 2, 41-55); Trusolino, L. and Comoglio, P. Nature Rev. Cancer 2002, 2, 289-300].
Met functions in tumorigenesis and tumor metastasis. Expression of Met along with its ligand HGF is transforming, tumorigenic, and metastatic (Jeffers, M. et al., Oncogene 1996, 13, 853-856; Michieli, P. et al., Oncogene 1999, 18, 5221-5231). MET is overexpressed in a significant percentage of human cancers and is amplified during the transition between primary tumors and metastasis. Numerous studies have correlated the expression of c-MET and/or HGF/SF with the state of disease progression of different types of cancer (including lung, colon, breast, prostate, liver, pancreas, brain, kidney, ovaries, stomach, skin, and bone cancers). Furthermore, the overexpression of c-MET or HGF have been shown to correlate with poor prognosis and disease outcome in a number of major human cancers including lung, liver, gastric, and breast. c-MET has also been directly implicated in cancers without a successful treatment regimen such as pancreatic cancer, glioma, and hepatocellular carcinoma.
Met mutants exhibiting enhanced kinase activity have been identified in both hereditary and sporadic forms of papillary renal carcinoma (Schmidt, L. et al., Nat. Genet. 1997, 16, 68-73; Jeffers, M. et al., Proc. Nat. Acad. Sci. 1997, 94, 11445-11500). HGF/Met has been shown to inhibit anoikis, suspension-induced programmed cell death (apoptosis), in head and neck squamous cell carcinoma cells. Anoikis resistance or anchorage-independent survival is a hallmark of oncogenic transformation of epithelial cells (Zeng, Q. et al., J. Biol. Chem. 2002, 277, 25203-25208).
Increased expression of Met/HGF is seen in many metastatic tumors including colon (Fazekas, K. et al., Clin. Exp. Metastasis 2000, 18, 639-649), breast (Elliott, B. E. et al., 2002, Can. J. Physiol. Pharmacol. 80, 91-102), prostate (Knudsen, B. S. et al., Urology 2002, 60, 1113-1117), lung (Siegfried, J. M. et al., Ann. Thorac. Surg. 1998, 66, 1915-1918), and gastric (Amemiya, H. et al., Oncology 2002, 63, 286-296). HGF-Met signaling has also been associated with increased risk of atherosclerosis (Yamamoto, Y. et al., J. Hypertens. 2001, 19, 1975-1979; Morishita, R. et al., Endocr. J. 2002, 49, 273-284) and increased fibrosis of the lung (Crestani, B. et al., Lab. Invest. 2002, 82, 1015-1022).
Anaplastic lymphoma kinase (ALK) belongs to the receptor tyrosine kinase (RTK) superfamily of protein kinases. ALK expression in normal adult human tissues is restricted to endothelial cells, pericytes, and rare neural cells. Oncogenic, constitutively active ALK fusion proteins are expressed in anaplastic large cell lymphoma (ALCL) and inflammatory myofibroblastic tumors (IMT) due to t2; chromosomal translocations. ALK has also recently been implicated as an oncogene in a small fraction of non-small-cell lung cancers and neuroblastomas (Choi et al, Cancer Res 2008; 68: (13); Webb et al, Expert Rev. Anticancer Ther. 9(3), 331-356, 2009).
Anaplastic large-cell lymphomas (ALCLs) are a subtype of the high-grade non-Hodgkin's family of lymphomas with distinct morphology, immunophenotype, and prognosis. ALCLs are postulated to arise from T cells and, in rare cases, can also exhibit a B cell phenotype. In addition, there are 40% of cases for which the cell of origin remains unknown and that are classified as “null”. First described as a histological entity by Stein et al. based on the expression of CD30 (Ki-1), ALCL presents as a systemic disease afflicting skin, bone, soft tissues, and other organs, with or without the involvement of lymph nodes. ALCL can be subdivided into at least two subtypes, characterized by the presence or absence of chromosomal rearrangements between the anaplastic lymphoma kinase (ALK) gene locus and various fusion partners such as nucleophosmin (NPM). Approximately 50-60% of cases of ALCL are associated with the t(2;5;)(p23;q35) chromosomal translocation, which generates a hybrid gene consisting of the intracellular domain of the ALK tyrosine kinase receptor juxtaposed with NPM. The resulting fusion protein, NPM-ALK has constitutive tyrosine kinase activity and has been shown to transform various hematopoietic cell types in vitro and support tumor formation in vivo. Other less frequent ALK fusion partners, e.g., tropomyosin-3 and clathrin heavy chain, have also been identified in ALCL as well as in CD30-negative diffuse large-cell lymphoma. Despite subtle differences in signaling and some biological functions, all fusions appear to be transforming to fibroblasts and hematopoietic cells. ALK fusion proteins have also been detected in a rare form of malignancy called inflammatory myofibroblastic tumor. Extensive analysis of the leukemogenic potential of NPM-ALK in animal models has further corroborated the importance of NPM-ALK and other ALK rearrangements in the development of ALK-positive ALCL and other diseases.
2-amino-pyridines, such as PF-2341066, have been reported as potent inhibitors of the HGF receptor tyrosine kinase (c-Met) and ALK (J. G. Christensen, et al. Abstract LB-271, AACR 2006 meeting; H. Y. Zou et al. Cancer Res 2007; 67: 4408; patent disclosures: WO 2004076412, WO 2006021881, WO 2006021886).

As there is still unmet need in treatment options for kinase mediated disease, it is desirable to create new and alternative approaches to addressing treatment and prevention of disease, disorders, or symptoms thereof.